Metal grid perimeter obstacle trap

Abstract

A continuous elongated trench is provided around a prison or military fortification. Parallel plates are provided on opposite side walls. Anti-personnel wires such as razor or barbed wire in concertina form are placed in the bottom or the trench. A light grid with large openings and weakened portions is placed over the trench and is supported on the plates. Anti-personnel explosives in the bottom of the trench and suspended within the trench beneath the grid deter crossing of the trench by persons, vehicles or objects. A covering over the grid blends the trench into the surrounding area.

I claim: 
     
       1. A horizontal anti-personnel security fence comprising an elongated trench surrounding an installation, anti-personnel wire at the bottom of the trench, a metal grid covering the trench, having openings of about 3×3 feet, the trench being to about 3 to about 5 feet deep, and being about 12 to about 24 feet across for dropping, trapping and injuring personnel attempting to breach the horizontal fence. 
     
     
       2. The apparatus of claim 1, further comprising anti-personnel explosives placed in the bottom of the pit. 
     
     
       3. The apparatus of claim 1, further comprising anti-personnel explosive devices suspended in the trench by hanging the devices along the metal grid. 
     
     
       4. The apparatus of claim 1, further comprising means for providing an electrical potential between the grid and the wires along the bottom of the trench for causing electrical injury to a person's body bridging the grid and the wires below in the bottom of the trench. 
     
     
       5. The apparatus of claim 1, further comprising random weakened areas in the grid for promoting breaking of the grid when crossed by unauthorized personnel. 
     
     
       6. The apparatus of claim 1, wherein the metal grid is loosely joined at intersections of the grid. 
     
     
       7. A metal grid obstacle personnel trap for surrounding prisons and military fortifications comprising a continuous trench about 4 feet deep extending around a prison or fortification, first and second opposite vertical walls on opposite sides of the trench, and anti-personnel wire at the bottom of the trench, a metal grid extending across the trench and covering the trench around the prison or fortification, the metal grid having square openings about 3 feet by about 3 feet for making it difficult to maintain a person's balance and for engaging the person by the wire within the trench if the person falls from th grid. 
     
     
       8. The apparatus of claim 6, further comprising anti-personnel explosives placed randomly in the bottom of the pit. 
     
     
       9. The apparatus of claim 6, further comprising anti-personnel explosive devices suspended in the trench by hanging the devices along the metal grid. 
     
     
       10. The apparatus of claim 6, further comprising means for providing an electrical potential between the grid and the wires along the bottom of the trench for causing electrical injury to a person's body bridging the grid and the wires below in the bottom of the trench. 
     
     
       11. The apparatus of claim 6, wherein a weak, light cover is placed over the grid to visually obscure the obstacle. 
     
     
       12. The apparatus of claim 7 wherein the anti-personnel wire is razor wire in concertina form. 
     
     
       13. The method of securing a perimeter of a prison or military fortification or the like, comprising digging an elongated trench around the prison or military fortification, placing anti-personnel wire within the trench, covering the trench with a metal grid and providing large openings in the grid about 3 feet by 3 feet. 
     
     
       14. The method of claim 13, wherein the providing of a grid comprises weakened portions in the grid for dropping a person crossing the grid into the trench and contacting the person with anti-personnel wire in the trench. 
     
     
       15. The method of claim 13, further comprising establishing an electrical potential between the grid and the wire in the trench for electrically injuring a person in contact with wire in the trench and thereby deterring persons from crossing the trench. 
     
     
       16. The method of claim 13, further comprising covering the grid with a decorative cover, thereby visually obscuring the trench and grid.